When you spend your time talking about volatile stuff like politics or, in my case, religion (especially that unique species of religion called “the Catholic faith”), you discover pretty quickly that conversations can move along two tracks simultaneously.

The first track is the “intellectual.” Somebody asks a question like, “Was the Gospel of John actually the testimony of John the Apostle?”

That’s a straightforward question with a straightforward answer: “Yes.” You can back it up with all sorts of evidence from the text itself, and from the testimony of the early Church, as well as a consensus of biblical scholars.

But many times, such questions are not purely intellectual. And that’s where the second track — a track involving the will — comes in.

We’ve all seen this kind of question. It generally manifests itself as the question that is meant to deny the very thing it ostensibly seeks to discover. This kind of question tends to be accusatory: “Aren’t you afraid to admit that there is absolutely no scholarly evidence that John the Apostle is the source of the Gospel of John?”

In short, there are two sorts of people: those who ask questions to find things out and those who ask questions to keep from finding things out.

When you point out that there is nothing to be afraid of and point such questioners to the appropriate scholarly evidence that John is, in fact, the source of his Gospel, you are greeted, not with “Thanks!” but with “Oh yeah?”

The “Oh yeah?” will often take the form of a sly attempt to change the terms of the original question: “The scholars who accept Johannine authorship are too conservative for me. I find the claims of ‘liberal’ scholars and skeptics more credible. The claims of ‘conservatives’ are not.”

Note the sleight of hand here. The original accusa-, er, question demanded any scholarly evidence. Now it has to be scholarly evidence from scholars the questioner approves of. And how do we know they are reliable scholars? Why, because they share the questioner’s opinion.

When you point out that the terms have changed, this will often lead to accusations that you are being unreasonable: “Are there any circumstances of evidence under which you’d abandon your religious beliefs?”

Reply that belief in Johannine authorship is not “religious” but the result of textual and historical evidence and you receive combinations of insults and irrelevancies: “Far too many Christians lie continually, with apparent gusto and verve, about the scientific facts when trying to justify their abortion or stem-cell research positions.”

The moving goalposts become more and more evident as the “argument” (if we can honor it with such an august term) dwindles from “There’s absolutely no scholarly evidence for John’s authorship” to “Well, okay, there’s evidence but I don’t like it” to “Christians are liars” to “Let’s talk about embryonic stem cells.”

As you might guess, this little snippet of conversation is a small digest of correspondence I had with an agnostic ex-Catholic who assured me that his reasons for leaving the faith were purely rational. I can’t tell you how often I’ve heard that from people who give remarkably little evidence of being motivated by, or even capable of, a rational — much less a purely rational — argument.

To be sure, there are rational people out there.

Some people are, in fact, too rational, having undergone the process of losing everything except their reason and becoming, as Chesterton said, madmen.

But conversations like this aren’t motivated by reason. They are motivated by a will that is seeking to heal some sort of personal wound.

Nobody leaves the faith because some obscure scholar is skeptical about whether John wrote his Gospel. Nobody leaves the Church because the manuscript of the Masoretic text is faulty at some points.

They leave because of pride, sin, pain, anger and all sorts of other intensely personal issues much closer to home.

For this reason, people who wish to bear witness to Christ should tread lightly since, as St. Ephraim observed, every man is fighting a great battle. But it is also the case that evangelists and apologists ought to point out the fact that those who engage in such rhetorical tactics are kidding themselves if they think they are being cold rationalists.

The diagnostic clue for the insincere questioner is the steadfast refusal to admit any answers that favor the Church’s case. When you encounter that drive to ask questions in order to keep from finding out what the Church teaches, the chances are good you are dealing not with difficulties of the intellect, but with a problem in the will.

Mark Shea is senior content editor for The Catholic Exchange.